科研之友
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摘要
J. Arhippainen and V. Muller showed that parallel to a + lambda e parallel to(1) <= 3 parallel to a + lambda e parallel to(op) for all a + lambda e is an element of (A) over tilde, where (A) over tilde is the unitization of an arbitrary non-unital Banach algebra A with regular norm. In this note, we present a necessary and sufficient condition for the equality of this estimate and its related problem.
- 出版日期2011-2
